public class Test {
    public static void main(String[] args) {
        String s="hello";
        char[] ch=s.toCharArray();//把字符串转变成数组
        for (char c: ch) {
            System.out.println(c);
        }
        char[] s1={'a','b','c','d'};
        String s2=new String(s1);//把数组转变成字符串
        System.out.println(s2);
    }
}
